Surgical device and method for pericardium retraction

ABSTRACT

A surgical device and method for retracting a pericardium tissue, the surgical device having a tissue-engaging member for providing a negative pressure suction force to the pericardium tissue which is sufficient to retract same. The surgical device may be positioned in a retracting configuration wherein it provides a tensile load on the contacted portion of pericardium tissue thereby also positioning the patient&#39;s heart, that is anatomically attached to the pericardium tissue, within the thoracic cavity of the patient. The surgical device may be temporarily coupled to a surgical platform in its retracting configuration.

FIELD OF THE INVENTION

The present invention relates to the field of surgical apparatus andmore specifically, to a tissue retraction device for positioning andorienting a beating heart during cardiac surgery.

BACKGROUND OF THE INVENTION

Coronary artery bypass graft (CABG) surgery is a widely practisedsurgical procedure for performing coronary artery revascularization orbypass grafts. This surgical procedure consists of replenishing oraugmenting blood flow to a portion of the patient's heart which is beingdeprived of such flow due to a restriction or blockage in a coronaryartery supplying the said portion of the patient's heart. A healthysegment from a blood vessel, such as an artery or a vein converted intoan artery, is attached to the patient's vasculature from a pointupstream of the coronary artery restriction or blockage to a pointdownstream thereof, thereby creating the bypass artery and associatedbypass blood flow. Since the great majority of CABG surgeries aremulti-vessel bypasses, this surgical procedure remains one of the mostcommon and effective treatments for coronary artery disease.

Traditional CABG surgery has been commonly performed through a midlinesternotomy incision, where the patient's sternum is incised and theribcage retracted to obtain access mainly to the patient's heart, thecoronary vessels, and other internal thoracic arteries. Intercostalthoracotomy approaches have also been employed whereby two adjacent ribsare spread apart, at times even removing a length of rib to improveaccess into the patient's thorax. In both approaches, a surgicalretractor is used to spread the patient's skin and bone structure and tomaintain an incised opening or surgical window onto the underlying heartand coronary vessels.

CABG surgery has been traditionally performed with the support of acardiopulmonary machine, whereby the patient's blood is oxygenatedoutside the body through extracorporeal circulation (ECC). This allowsthe surgeon to perform surgical procedures on a near perfectly stillheart while the patient's life support is maintained by cardiopulmonaryassistance. During traditional CABG surgery, the surgeon or assistantmay manually or otherwise manipulate the arrested heart into a positionand orientation that yields the best access to the target arteryrequiring the bypass graft. The great majority of CABG surgeries(approximately 70%) are triple vessel bypass surgeries; that is, atleast one bypass graft is performed on each of the anterior, inferiorand posterior artery beds of the patient's heart.

Recently, in an aim to render CABG surgery less invasive to the patient,beating heart CABG surgery is being developed whereby ECC, one of themost invasive aspects of cardiac surgery, is eliminated and coronaryartery revascularization is performed directly on the beating heart. Oneof the challenges in performing beating heart CABG surgery lies inpositioning and orienting the beating heart in order to obtain access tothe inferior and posterior artery beds, while aiming to minimizephysiologically undesirable effects such as hemodynamic instability,arrhythmia, or a precipitous drop in arterial pressure, any of which mayoccur as a result of such beating heart manipulation. Furthermore, asurgical device which enables manipulation of the beating heart or whichrestrains its movement or positioning may impose loads and constraintson the beating heart. This may impede the normal beating function of theheart and induce the onset of the physiologically undesirable effectsdescribed above. In traditional CABG surgery, the heart is arrested andtherefore heart manipulations are well tolerated.

During CABG surgery or beating heart CABG surgery, the pericardium,namely the substantially thin membranous tissue forming a sac in whichthe heart and the commencement of the major blood vessels connectingwith the heart are contained, is generally incised and unraveled toexpose at least a portion of the heart surface which is to receive thebypass graft. The pericardium tissue, unlike the heart, is not beatingand it may be separated from the heart surface except in certainlocations where it is anatomically attached to the heart. Thus, it issurgically possible in CABG surgery to position and orient the heartthrough retraction, positioning and loading of the pericardium tissue toobtain access to the inferior and posterior coronary artery beds. Inbeating heart CABG, heart manipulations achieved through retraction ofthe pericardium tissue tends to reduce the likelihood of inducing traumato the beating heart and tends to minimize the physiologicallyundesirable effects mentioned above, since direct contact with thebeating heart is avoided. One such beating heart manipulation consistsof “verticalizing” the heart in order to gain access to the posteriorartery bed. In this maneuver, the pericardium is engaged close to thebase of the heart, preferably 1.5 inches from pericardial reflection,and the apex of the heart is rotated outward from retracted chest cavitythrough the tensile loads applied to the engaged pericardium. Thelongitudinal axis of the beating heart thereby assumes a substantiallyvertical orientation.

The desired position and orientation of a beating heart may bemaintained, at least in part, by maintaining retraction loads applied tothe pericardium tissue and securing the surgical apparatus that appliesthe tensile load to pericardium tissue. During CABG surgery, a deployedsurgical retractor provides a suitable stable platform for thesecurement of the pericardium retraction loads. The pericardium tissuemay be engaged by a variety of methods. Sutures such as traction or staysutures have been generally employed in cardiac surgery to retracttissue during a surgical intervention. Traditionally sutures consist oftissue piercing member such as a relatively sharp needle and a length ofwire-like filament such as a suture line integrally attached to theblunt end of said needle. Pericardium retraction may be achieved throughthe application of pericardial traction sutures whereby the needlepierces the pericardium tissue, threading a certain length of sutureline through the pierced pericardium tissue, and pulling simultaneouslyon both the resulting lengths of suture line; that is, the lengthbetween the pierced tissue and the free end of the suture line, and thelength between the pierced tissue and the needle-bearing end of thesuture line, to displace the pericardium tissue and consequently thebeating heart anatomically attached to the pericardium.

In order to “verticalize” a beating with pericardial traction sutures, anumber of such sutures must be inserted through and engaged with thepericardium tissue preferably along its pericardial reflection in orderto get the desired lifting of the heart apex and consequently the bestexposure to the posterior coronary bed. For example, one traction suturemay be placed between the superior and inferior pulmonary vein, a secondone below the inferior pulmonary vein, a third one midway between theapex of the heart and the inferior pulmonary vein, and a fourth onetowards the diaphragmatic face near the inferior vena cava. Pericardiumretraction loads are subsequently applied to each of these tractionsutures independently. The resulting lengths of suture line must then besecured to a stable surgical platform such as the sternum retractor tomaintain the desired retraction load on the pericardium tissue.

During the placement of these pericardial traction sutures deep withinthe patient's thorax and close to the base of the beating heart, thesurgeon's view of the body tissue contained beyond the unraveledpericardium tissue is hindered. Consequently, because of this blindinstallation, the risk of unintentionally puncturing other underlyingbody tissue with the tissue piercing needle may lead to operative orpostoperative complications, especially when a number of such sutures isrequired. For instance, an inadvertent puncture of the pleura and lungsmay lead to a pneumothorax injury if undetected. The placement of deeppericardial traction sutures may therefore be challenging.

Pericardial traction sutures may be characterized by additionaldrawbacks. For example the placement of such sutures may be timeconsuming, since securing of the pericardium retraction load through themanual tying of the suture line lengths is often a multiple stepthreading and knotting procedure. As well, the placement of pericardialtraction sutures may in some instances be cumbersome due to poor accessto the deeper portions of pericardial tissue and due to the number oftraction sutures required to achieve beating heart “verticalization”.Lastly, these sutures may not be conducive to permitting easyreadjustment of the magnitude of the desired tensile load on thepericardium tissue, or of the direction of said load relative to thepericardium tissue. Typically readjustments of this type may require asurgeon to untie and retie suture line lengths or to cut the existingsuture line having the undesired retraction load and replace it with anew suture that must repierce the pericardium tissue and again besecured.

Generally, adjustment of the desired tensile load on the pericardiumtissue by cutting an existing suture line and repiercing a new sutureline is not desirable. First, the process of placing a pericardialtraction suture requires considerable manual dexterity, at timesrequiring the help of an assistant. The process is therefore tedious andtime consuming. Second, a repiercing of the pericardium tissue with asubsequent traction suture tends to increase the likelihood of inducingtissue trauma or tissue tearing which may have to be surgicallyrepaired.

Based on the foregoing, it would be advantageous to provide a means forpericardium retraction which is less invasive to the pericardium tissueand underlying coronary tissue, and which is not compromised by asurgeon's lack of vision behind the pericardium tissue. Since thepericardium is a relatively thin, membranous tissue which is incised andunraveled to expose the underlying heart surface prior to performingcardiac surgery, it would be advantageous to have the pericardium tissueengaged by a negative pressure suction force. It would be a furtheradvantage to have the pericardium contacting perimeter of the negativepressure suction device constructed from a substantially flexiblematerial which conforms to variations in anatomy, and which deflects toform a substantial seal when placed in contact with the pericardium andactivated by a negative pressure suction force.

Subsequent to securing the desired position and orientation of thebeating heart through retraction of the pericardium tissue, coronaryartery revascularization may be achieved by locally immobilizing a smallportion of the beating heart around the target artery requiring thebypass graft through a variety of ways. One such method consists ofimmobilizing the portion of beating heart around the target arterythrough the application of a mechanical compression by virtue of acoronary stabilizer. The remaining portions of the heart continue tobeat while the target artery site is immobilized during the bypass graftprocedure. One such surgical apparatus for achieving this method ofmechanical immobilization has been described in copending Canadianpatent application Serial No. 2,216,893 filed on Sep. 30, 1997 in thenames of Cartier and Paolitto and entitled “Sternum Retractor forPerforming Bypass Surgery on a Beating Heart”. Alternatively, a negativepressure suction has also been used in beating heart CABG to locallyimmobilize a portion of the beating heart surface in the vicinity of thetarget artery requiring the bypass graft. An associated device whichapplies the suction force to the beating heart surface is subsequentlysecured relative to a stable platform. In this case, the suction port orthe structural members of the associated device that applies thenegative pressure force must be substantially rigid since the primarypurpose of the device is to attempt to immobilize and render motionlessthat portion of heart tissue it engages in order to create a stablesurgical field, while the rest of the heart continues to beat.

U.S. Pat. No. 5,727,569 issued to Benetti et al. on Mar. 17, 1998 andentitled “Surgical Devices for Imposing a Negative Pressure to Fix thePosition of Cardiac Tissue during Surgery”, describes a surgical devicefor imposing a negative pressure directly on a portion of the outersurface of the beating heart. The Benetti device is applied proximate toor surrounding the portion of the outer surface of the beating heart atwhich a surgical intervention is to occur. By applying negative pressureby means of the Benetti device, the motion of the outer surface of thebeating heart is restricted at the particular area where the surgeon isworking. The Benetti reference therefore relates to alleviating theproblem of performing extremely delicate surgical procedures, likebypass grafting, during which contractions of the beating heart causethe target artery surface of the heart to move continuously. Benetti etal. teach a method of locally and directly immobilizing the targetartery location during a surgical intervention intended to occur withinthe immobilized region.

In contrast to the teachings of the prior art, the present inventionherein described relates to surgical manipulation of the pericardium,which is the substantially conical membranous sac in which the heart andthe commencement of the major vessels are contained. The Benettireference does not teach or suggest the positioning and orienting of theentire beating heart as a whole, nor is there any teaching or suggestiontherein of retraction of the pericardium to achieve surgical access inan area of the beating heart away from where pericardium retractiondevice is deployed. Rather, Benetti et al. apply suction around or closeto the portion of beating heart tissue proximal to the area where thesurgical intervention is to be performed. More specifically, theteachings of Benetti et al. result in immobilization of the pulsatingeffects of a portion of the exterior surface of the beating heartthrough negative force application at the target artery site. It wouldbe advantageous to be able to position the beating heart through thedeployment of the device in a location remote to the desired site ofsurgical intervention to tend to facilitate the access and approach ofsurgical instruments, and to tend to improve the ergonomics of thegrafting site and direct visibility thereto. Unlike the teachings of theBenetti reference, which results in the application of suction directlyon the beating heart, it would instead be advantageous to apply thissuction indirectly on a benign, non-beating part of coronary organtissue. This will tend to not impede, restrain or restrict the functionof the beating heart.

Benetti et al. describe a device with multiple suction ports attachedthrough a negative pressure manifold. In the teachings of Benetti, it issuggested to provide a device having suction ports which share a commonnegative pressure manifold. However, in such a suggested device, if onesuction port is not in contact with underlying tissue to form a seal,then the entire system will tend to be rendered ineffective, at least inpart, by the leakage through said port. It would be advantageous tointroduce a feature which cuts off flow through non-sealing suctionports with cardiac tissue, thereby tending to maintain effective theentire set-up even if only a portion of the suction ports are properlysealing with the said tissue. Alternatively, Benetti et al. teach thateach suction port can have it own independent supply line, which wouldcircumvent this problem through a more complex, cumbersome, andpart-intensive set-up. The new invention described herein introduces anembodiment thereof which allows the surgical apparatus, namely thepericardium retraction device, to function with at least a portion ofthe suction ports in contact with the coronary organ tissue. Thisembodiment can be applied to other surgical apparatus engaging coronaryorgan tissue through a negative pressure suction force.

The Benetti reference describes either fixing the suction port device toa rigid support during the procedure, or having the suction port deviceas a part of a hand-held instrument with a handle structure connectedthereto and adapted to being grasped by a human hand. In contrast to theteachings and suggestions of the Benetti reference, it may beadvantageous to attach a suction port device to an intermediatepositioning means prior to fixturing the complement to a stable surgicalplatform such as a sternum retractor, in order to achieve flexibility inthe surgical set-up to attempt to cater said surgical set-up to distinctpatient anatomies.

According to the Benetti teachings, the negative pressure suction is theonly input means for activating the device to engage the underlyingbeating heart tissue. If the suction is lost, the loss will lead to thesurgical work-site of the beating heart no longer immobilized andresulting instability from pulsating effects. If other instruments arein contact with the heart at this time, it may also lead to risk oftrauma or injury.

In the pericardium retraction device according to the present invention,it would be advantageous to have a design feature in the tissue-engagingmember that is activated by the negative pressure suction therein,whereby said design feature comes into contact with a portion of theengaged pericardium tissue and is capable of transmitting a mechanicalforce to the pericardium tissue being retracted. It would be a furtheradvantage if this said mechanical force remains as a back-up feature inthe eventuality that the suction force is interrupted or lost. Theembodiment of the invention described herein can be applied to all othersurgical apparatus engaging coronary organ tissue.

In “verticalizing” the beating heart through retraction of pericardiumtissue, it may be advantageous in some instances to incorporate in thepericardium retraction device a bracing member which engages on the apexof the “verticalized” beating heart, and thereby tends to facilitatein-process re-adjustments of the position and orientation of the entirebeating heart by the movement of the surgical apparatus comprising thepericardium retraction device together with the apex-bracing member.

In light of the foregoing it would therefore be advantageous to have adevice which acts on a portion of the pericardium tissue, in a locationremote to the target artery site where the surgical intervention willtake place, to aim to achieve the beating heart manipulations in a leastinvasive, hemodynamically stable manner, wherein the device would notmaterially interfere with the normal beating function of the heart. Itwould be a further advantage if this device would act in an area remoteto where the surgical intervention is to occur, thereby tending toimprove the surgeon's direct vision and ergonomics of the surgicalwork-site.

Although the present invention will focus on cardiac surgery, and morespecifically CABG surgery performed directly on a beating heart, theprinciples and concepts may be applied to other types of surgery orsurgical interventions that may benefit from the positioning andorientation of a body organ through the retraction of membrane-like bodytissue anatomically attached to the said body organ, and capable ofbeing engaged by a negative pressure suction force.

It is therefore an object of the present invention to provide aretraction device that allows the indirect manipulation of a beatingheart as a whole through the application and maintenance of a tensileload on the non-beating pericardium tissue anatomically attached tobeating heart, and where said pericardium tissue is engaged by anegative pressure suction force.

It is another object of the present invention to engage the non-beatingpericardium tissue without piercing therethrough and thereby tending tominimize risk of inducing trauma or damage to organs or tissue behind oradjacent the pericardium.

It is a further object of the present invention to attempt to facilitateposterior artery grafts on the beating heart through indirectmanipulation of the beating heart, such that the undesirablephysiological effects associated with direct contact manipulation of thebeating heart might be alleviated or avoided.

It is a further object of the present invention to attempt to positionand orient a beating heart as a whole without the necessity of directlycontacting the pulsating heart surface and without materially impedingor restricting the natural beating function of the heart, therebypromoting a reduction in the likelihood of producing undesirablephysiological effects associated with direct contact manipulation of thebeating heart.

It is another object of the present invention to attempt to position andorient the beating heart indirectly through a device acting at a remotelocation away from the target work-site on said beating heart where thesurgical intervention is to be performed.

It is an additional object of the present invention to attempt to applythe concepts and principles of the present invention as they relate tobeating heart CABG to other suitable types of surgery which may requireretraction of membrane-like body tissue engaged through a negativepressure suction force.

SUMMARY OF THE INVENTION

According to one broad aspect of the present invention, there isprovided a surgical apparatus for retraction of tissue, the surgicalapparatus comprising a tissue-engaging member for providing on thetissue a negative pressure suction force which is sufficient to retractsame, the tissue-engaging member having a deformable skirt for contactwith the tissue, the deformable skirt defining a contacting perimeterfor substantially air-sealed engagement with the tissue, and wherein anegative pressure plenum is formed within the deformable skirt when thetissue engaging member is operatively connected to a negative pressuresource and when the contacting perimeter of the deformable skirt isplaced against the tissue in substantially air-sealed engagementtherewith.

BRIEF DESCRIPTION OF THE DRAWINGS

For better understanding of the present invention and to show moreclearly how it may be carried into effect, reference will now be made byway of illustration and not of limitation to the accompanying drawings,which show an apparatus according to the embodiments of the presentinvention, and in which:

FIG. 1 is a perspective view of a first embodiment according to thepresent invention illustrating the deployment of a pericardiumretraction device oriented and positioned within a surgical workspace bya positioning means attached to a sternum retractor;

FIG. 2 is a partially dismantled isometric view of the pericardiumretraction device illustrated in FIG. 1;

FIGS. 3A to 3C schematically illustrate various dispositions of adeformable skirt means of a pericardium retraction device according tothe first embodiment of the present invention comprised of asubstantially circular tissue-engaging perimeter;

FIGS. 4A to 4D illustrate several variants of a tissueingestion-limiting means of the pericardium retraction device of thefirst embodiment of FIGS. 1 and 2;

FIG. 5 is a perspective view of a pericardium retraction deviceaccording to a second embodiment of the present invention comprised of aplurality of tissue engaging members in the form of suction ports;

FIG. 6 is an exploded view of the pericardium retraction deviceaccording to the second embodiment of the present invention illustratedin FIG. 5;

FIG. 7 is a perspective view of the pericardium retraction deviceaccording to the second embodiment of the present invention shown inFIG. 5 illustrating the engagement of the pericardium retraction devicewith pericardium tissue;

FIGS. 8A to 8D illustrate several variants of tissue-grasping means ofthe tissue-engaging member of the second embodiment of FIG. 5;

FIG. 9A is a perspective, cross-sectional view illustrating apericardium retraction device according to a third embodiment of thepresent invention comprising a valve means shown in a closed,non-deployed state;

FIG. 9B is a perspective, cross-sectional view illustrating apericardium retraction device according to the third embodiment of FIG.9A with the valve means shown in an open, deployed state;

FIG. 10 is a perspective, elevational view of a pericardium retractiondevice according to a fourth embodiment of the present inventioncomprising a bracing member engaged with the apex of a beating heart;

FIG. 11 is an exploded view of the pericardium retraction device andassociated bracing member according to the fourth embodiment of thepresent invention illustrated in FIG. 10;

FIGS. 12A to 12D illustrate several variants of the apex-contactingmember of the bracing member according to the fourth embodiment of thepresent invention illustrated in FIGS. 10 and 11;

FIG. 13 is a perspective view of a pericardium retraction deviceaccording to a fifth embodiment of the present invention, comprising aplurality of independent tissue-engaging members;

FIG. 14 is a perspective view of a pericardium retraction deviceaccording to a sixth embodiment of the present invention, comprising aplurality of independent tissue-clamping members;

FIG. 15 is a cross-sectional, elevational view of a pericardiumretraction device according to a seventh embodiment of the presentinvention, comprising a conduit means which is provided through a memberof the positioning means.

DETAILED DESCRIPTION OF THE INVENTION

The features and principles of this invention can be applied, in wholeor in part, to other types of cardiac surgery requiring the strategicpositioning and orientation of a beating heart as a whole organ. By wayof illustration, the description of the embodiments that followsherebelow will however focus on applying the features and principles tobeating heart CABG surgery.

In part, the embodiments of this invention may advantageously beapplied, if desired, to the surgical retractor and positioning meansdescribed in above-referenced copending Canadian patent applicationSerial No. 2,216,893, the contents of which are incorporated herein byreference. This existing application has been assigned to CORONEO Inc.,the assignee of the present application. Alternatively, the embodimentsof the invention may also be applied to other types of surgicalretractors and other types of positioning means capable of securing thepericardium retraction device according to the present invention in asubstantially stable orientation and position relative to the surgicalretractor. Alternatively, the surgical retractor may be replaced byother substantially stable surgical platforms that may be engaged withthe positioning means to secure the pericardium retraction deviceaccording to the present invention. Such surgical platforms wouldinclude: a surgical table, a surgical bridge or truss or truss memberattached to a surgical table and spanning the patient or set adjacent tothe patient, or other like platforms.

During the course of a cardiac surgery, a surgeon needs to performcertain tasks within a surgical workspace (labelled “W” in FIG. 1). Thisworkspace W is defined by an area that contains generally the perimeterof a deployed sternum retractor and a buffer zone therebeyond, with thearea extending below generally to the depth of the patient's thorax, andabove generally to the height above the retracted chest cavity in whichthe surgical apparatus is contained and manipulated.

By way of a general overview and with reference to FIG. 1, a surgicalapparatus with which the invention may be used is comprised of threemain components, a pericardium retraction device 1, a positioning meanssuch as positioning and articulation mechanism 20 and a sternumretractor 2. The sternum retractor 2 is illustrated in its deployedstate, thereby creating and maintaining the surgical window thatprovides the surgeon with access to the patient's internal coronaryorgans, which include the heart, the pericardium tissue, the aorta andvena cava, the coronary arteries and veins, the pleurae, the thymus, andother anatomical features.

The sternum retractor 2 includes four major parts: (i) an elongated rackbar 5, (ii) a first retractor spreader arm 3 being preferably fixed tothe rack bar 5, (iii) a second retractor spreader arm 4 being preferablymovable with respect to the rack bar 5, and (iv) an actuator 6 foreffecting movement of the retractor spreader arm 4 relative to retractorspreader arm 3.

Retractor spreader arms 3 and 4 extend in a direction substantiallytransversely with regard to the rack bar 5, generally in the samedirection therefrom and in a parallel orientation with respect to oneanother. The movable arm 4 can be displaced along the rack bar 5, andrelative to the other arm 3, preferably through the rotation of theactuator 6 activated by the surgeon. The actuator 6 is operativelyconnected to the rack bar 5 and to the other spreader arm 4, and istranslatable along the length of the rack bar 5. This is preferablyachieved by the engagement of a pinion mechanism (not shown) of actuator6 with the rack teeth on rack bar 5. Two retractor blades 7 and 8 arerespectively provided with the retractor spreader arms 3 and 4,preferably disposed below the rack bar 5 when the sternum retractor 2 isdeployed on a patient. The retractor blades 7 and 8 engage with andserve to retract a portion of the patient's incised skin, the two halvesof the patient's incised sternum and the patient's ribcage therebyexposing the coronary organs to be operated on through the resultantsurgical window. When viewing the resultant surgical window from abovethe patient, the retractor arms 3 and 4 of the deployed sternumretractor 2 each have a generally arcuate orientation.

The sternum retractor 2 advantageously comprises arcuate rails 70 and 80along the top of arcuate retractor spreader arms 3 and 4, respectively.The rails 70 and 80 configure an inverted T-slot arcuate passage 71 and81, respectively, preferably centrally located within said rails, andpreferably extending throughout the entire arcuate length of said rails.A similar linear longitudinal rail 50, may also be configured along thetop of rack bar 5. Longitudinal rail 50 is also configured with aninverted T-slot longitudinal passage 51, preferably extending throughoutits entire longitudinal length. These said rails form a mountingperimeter that can advantageously serve to engage a positioning andarticulation mechanism 20 that may be utilized to place a variety ofmechanical coronary stabilizers during beating heart CABG surgery, forinstance, as described in previously mentioned Canadian applicationSerial No. 2,216,893. Alternatively, the positioning and articulationmechanism 20 may also be utilized to set a pericardium retraction device1 in a substantially stable position and orientation within the surgicalworkspace W. As well, these rails can also be utilized to engage othersurgical apparatus, that may need to be secured along the perimeter ofthe sternum retractor 2 during cardiac surgery.

A plurality of slit-like channels 72 and 82 are configured along thearcuate arms 3 and 4 and cut through the arcuate rails 70 and 80,respectively. FIG. 1 illustrates three such slit-like channels 72 on theretractor spreader arm 3 and three such slit-like channels 82 on theretractor spreader arm 4. The slit-like channels 72 and 82 extenddownwards from the top of the rails 70 and 80 to a depth preferablybelow the entire depth of the inverted T-slot arcuate passages 71 and81, preferably by an amount equivalent to the width of said slit-likechannel. The slit-like channels 72 and 82 in the present invention areconfigured so that a wire-like filament will not restrict or otherwisehinder the functionality of the positioning and articulation mechanism20 when such mechanism becomes engaged in said passages 71 and 81 ofsaid rails 70 and 80, provided the wire-like filament is placed in thedeepest position within said slit-like channel, as is the case in someof the embodiments of the present invention to be described in greaterdetail below.

As further illustrated in FIG. 2, the first embodiment of a pericardiumretraction device 1 according to the present invention is comprisedmainly of a tissue-engaging member 30, a device manipulating means suchas shaft member 13, a conduit means such as conduit passage 10, and asuction line interface means such as pneumatic fitting 11. Thetissue-engaging member 30 is of a substantially arcuate shape whenviewed along the longitudinal axis of shaft member 13. It is furthercomprised of a substantially-elastic sheath 31 serving as an outer shellthat is insertable over a substantially-rigid inner structure 32. Innerstructure 32 is substantially air permeable. For instance the innerstructure may be designed and produced with an open configurationstructure, such as a perforated sheet structure or a truss-like spaceframe structure. Inner structure 32 is rigidly attached at one sidethereof to shaft member 13 in the vicinity of source orifice 14, ineither a permanent or demountable assembly. At another side thereof,inner structure 32 is capped by a substantially planar tissueingestion-limiting means such as ingestion-limiting baffle 33.Ingestion-limiting baffle 33 is also of a substantially rigid andsubstantially open configuration.

Sheath 31 is configured with a cut-out slot 317 that allows it to slideover pneumatic fitting 11 and shaft member 13, prior to fitting overinner structure 32. The cut-out slot 317 must be sufficient to allowinsertion over any protrusions, such as manipulation handle 12 whilestretching the elastic sheath 31, if necessary to facilitate insertion.

The proximal end of the shaft member 13 is configured with a pneumaticfitting 11 which will allow hook-up to a negative pressure source, suchas commonly available in most operating rooms. In this first embodiment,the shaft member 13 is substantially tubular thereby configuring anintegral conduit passage 10 which serves to communicate the proximalpneumatic fitting 11 with the distal tissue-engaging member 30. Thistends to result in an unencumbered, more ergonomic surgical workspace W,free from connections to peripheral conduits and equipment that mayotherwise be disposed in the vicinity of the surgical intervention site.Alternatively, the conduit passage 10 may be a separate tubular lineeither housed inside at least a portion of the shaft member 13, orrunning alongside at least a portion of the said shaft member.

During multiple vessel beating heart CABG, the pericardium sac isincised usually along the anterior surface of the beating heart andalong the long axis of the heart. The pericardium tissue is subsequentlyunraveled from the surface of the beating heart to expose at least aportion of the beating heart that will undergo the bypass graft surgicalintervention. More specifically, during coronary arteryrevascularization of an inferior or posterior artery such as thecircumflex artery (Cx), posterior descending artery (PDA), obtusemarginal artery (OM), or postero-lateral artery (PLA), the surgeon orassistant will position the pericardium retraction device 1 in a mannerthat engages the tissue-engaging perimeter 311 thereof with a portion ofthe pericardium tissue. During the coronary revascularization of theseabove mentioned arteries, it is preferable to engage the pericardiumretraction device 1 with the side of the pericardium tissue that was incontact with the heart surface prior to the incision of said tissue, andalso preferable to engage pericardium retraction device 1 at a locationapproximately 1.5 inches away from the interface where the pericardiumtissue is anatomically attached to the beating heart and the majorvessels. A tissue-engaging member 30 with a substantially arcuate shapeis advantageous for engaging the pericardium tissue along this saidinterface.

With suction introduced, a negative pressure plenum is formed by theinside surface 312 of sheath 31 and the top of the pericardium tissuethat is engaged within the tissue-engaging perimeter 311 of said sheath.A substantial seal between the outer shell formed by elastic sheath 31and the top surface of the pericardium tissue along perimeter 311, andanother substantial seal between the said sheath and inner structure 32along cut-out 317, render said negative pressure plenum as non-flowingwhereby the airflow through tissue-engaging member 30 is temporarilyinterrupted by its engagement with the pericardium tissue. The suctionforce exerted through the tissue-engaging member 30 serves to engage thepericardium tissue, but also to adhere the inner surface 312 of theelastic sheath 31 against the rigid open configuration surfaces of innerstructure 32. At least one conduit passage 10 must be in communicationwith said non-flowing negative pressure plenum to supply suction forceto engaged pericardium tissue.

In this first embodiment, elastic sheath 31 may be produced from anysuitable polymeric material approved for surgical use. Depending on thepolymeric material selected, the elastic sheath 31 may be disposablethereby tending to facilitate the cleaning and sterilization ofunderlying inner structures 32 and 33 which preferably form a reusableassembly. Alternatively, the elastic sheath 31 may be reusable providedthe sheath's polymeric material properties are well-suited to and do notdegrade after repeated sterilization cycles. Alternatively, if thepolymeric material properties degrade after several sterilization cyclesthe sheath 31 may be replaced at regular intervals after a certainnumber of surgeries.

Sheath 31 may be designed to have variable elastic properties throughoutits shape either by virtue of its variable thickness or by virtue of itsvariable composition during fabrication. Reinforcement fibers may alsobe used in the fabrication of the polymeric sheath 31 to bias itselasticity along certain axes. This is especially beneficial where theinner structure 32 and shaft member 13 are rigid, whereby elastic sheath31 acts as a buffer in elastic gradient between said rigid members 32and 13 and non-structural membrane-like pericardium tissue. This bufferin elastic gradient may encourage the membrane-like pericardium tissueto remain in compliant contact with tissue-engaging perimeter 311 ofsaid sheath.

Once sheath 31 is fully assembled over inner structure 32, thetissue-engaging perimeter 311 extends outwardly beyond the innerstructure perimeter 321. This flexible and substantially elasticprotrusion tends to provide flexibility in the design to cater todifferent patient anatomies and to assist with some degree of ingestionof the pericardium tissue by the tissue engaging member 31 regardless ofvariations in anatomy. Ingestion of the pericardium tissue is discussedin greater detail below.

The open area perimeter of sheath 31 is configured with a tapered andbeveled terminal edge in the nature of a deformable skirt 316, as bestshown in FIGS. 2 and 15. Extending outwardly beyond inner structureperimeter 321, this deformable skirt 316 achieves a substantiallycompliant seal perimeter at tissue-engaging perimeter 311, capable ofengaging the pericardium tissue throughout a range of spatialorientations which the pericardium tissue may assume relative to innerstructure 32. The deformable skirt 316 provides readjustment of thesubstantially planar surface formed by tissue-engaging perimeter 311depending on the direction of application of tensile retraction loadsapplied to and reacted by the pericardium tissue. A tensile retractionload applied to the pericardium tissue in a direction substantiallyparallel to the axis of shaft member 13 distorts the beveled edge ofdeformable skirt 316 equally around the tissue-engaging perimeter 311,in an inward direction toward the center of said tissue-engagingperimeter 311. If the tensile retraction load is applied to thepericardium tissue in a skewed direction relative to the axis of shaftmember 13, the beveled edge of skirt 316 will distort unevenly aroundthe tissue-engaging perimeter 311 in a fashion that the substantiallyplanar surface formed by tissue-engaging perimeter 311 is now orientedsubstantially perpendicular to the direction of application of saidmanipulation force or substantially perpendicular to the pericardiumreaction force to imposed retraction loads. This is better illustratedin FIGS. 3A-3C, and explained in this case with a single tissue-engagingmember such as suction port 34 which has substantially circulartissue-engaging perimeter 341. Apart from the cross-sectional shape ofthe suction port 34, it generally provides a construction similar tothat of tissue engaging member 30. By virtue of the deformable skirt342, the substantially planar surface formed by tissue engagingperimeter 341 engaged with pericardium tissue may assume a virtuallyinfinite number of spatial orientations. These spatial orientations maybe defined by a vector (not shown) that passes through the center ofperimeter 341 and is normal to the substantially planar surface formedby said perimeter 341 lying within a substantially conical volume ofangle φ (not shown) relative to the centerline of suction port 34.

The ingestion-limiting baffle 33 illustrated in FIG. 2, ensures that thepericardium tissue will not be entirely ingested within inner structure32 (if said baffle is not present), but ingested the optimum amount toregulate the suction forces on the engaged pericardium tissue derivedfrom negative pressure acting thereon. Since the source orifice 14 forthe negative pressure is typically much smaller in area than the arearequired to achieve the desired suction force through tissue-engagingmember 30, the ingestion-limiting baffle 33 serves to ensure the suctionforce reacts on a much larger area of pericardium tissue. The structuralintegrity of the ingestion-limiting baffle 33, combined with the innerstructure 32, ensure the structural perimeter 321 remains open tomaintain the desired suction force. Furthermore, structural perimeter321 must remain substantially rigid to keep elastic sheath 31 fromrippling along its tissue engaging perimeter 311 due to the effect ofthe negative pressure suction. This rippling would tend to render moredifficult the compliance of the pericardium to the tissue engagingperimeter 311, since such tissue would be required to conform to theirregular shape of the rippled perimeter. The pericardium tissue ispartially ingested within tissue-engaging member 30 by an amountsubstantially equal to the extension of tissue-engaging perimeter 311 ofsheath 31 beyond structural perimeter 321 of inner structure 32. Theingested pericardium tissue contacts the ingestion-limiting baffle andassumes a shape conforming to the shape of the said baffle.

The tissue ingestion-limiting baffle 33 preferably forms an integralassembly with the open internal structure 32, whereby it may bedemountably assembled with mechanical fasteners or by virtue of aclipped-in assembly, or it may be permanently mounted by gluing,welding, brazing, or other like means along perimeter 321.Alternatively, the tissue ingestion-limiting means may be part ofelastic sheath 31, for instance finger-like protrusions extending frominner surface 312 in a direction normal thereto.

Variations in the open configuration of ingestion-limiting baffle 33 areillustrated in FIGS. 4A-4D. FIG. 4A illustrates an ingestion-limitingbaffle with substantially circular perforations 331, FIG. 4B illustratesa baffle with webs defined by substantially triangular perforations 332,FIG. 4C illustrates a baffle with webs defined by substantially squareperforations 333, and FIG. 4D a baffle with webs defined bysubstantially rectangular perforations 334. Other like openconfigurations for the tissue-ingestion baffle are possible withoutdeparting from the spirit of the present invention. As those skilled inthis art will appreciate, the resulting suction force on the engagedpericardium is partly a function of the open area through baffle 33based on its perforation density.

The substantially open configuration inner structure 32 may beconfigured with the same variations in construction as the tissueingestion-limiting baffle 33, that is, webs defined from a variety ofperforations.

The shaft member 13 is may comprise a manipulation handle 12 for thesurgeon to manipulate, orient, and position the pericardium retractiondevice 1. The desired verticalization of the beating heart is achievedby the application of a tensile load to the pericardium tissue by thesurgeon's manipulation of the pericardium retraction device 1 that isengaged with a portion of pericardium tissue by virtue of a negativepressure suction force. Heart verticalization is achieved in an indirectmanner whereby the beating heart is not in direct contact with theenabling surgical apparatus in the nature of a pericardium retractiondevice. Moreover, the pericardium retraction loads tend not to imposeany considerable restriction on the beating function of the heartthereby increasing the likelihood of achieving hemodynamically stablebeating heart manipulations.

The desired pericardium retraction load or the desired heartverticalization is maintained by securing the pericardium retractiondevice 1 to the sternum retractor 2 through the positioning andarticulation mechanism 20. The positioning and articulation mechanism 20is preferably comprised of a first joining member such as a firstarticulation member in the nature of a cylindrical post 21 and a secondjoining member such as a second articulation member in the nature of aspherical clamp 22, each capable of providing a multitude of motiondegrees of freedom. Shaft member 13 is inserted in between the clampingmembers of spherical clamp 22. The clamping members may engage the shaftmember 13 anywhere along its longitudinal length. Final adjustments tothe pericardium retraction load may also occur with the shaft member 13engaged between clamping members of spherical clamp 22 before the entirepositioning and articulation mechanism 20 assembly is rigidly securedthrough the action of each of the tensioning knobs of spherical clamp 22and cylindrical post 21.

In-process readjustments to the pericardium retraction load may alsooccur by loosening one or both of each said tensioning knobs, and notdisengaging the pericardium retraction device 1 from the spherical clamp22. With the tensioning knob of spherical clamp 22 slightly loosened,the pericardium retraction device 1 is free to translate through theclamping members of spherical clamp 22, rotate about the axis of shaftmeans 13, pivot about axis of rod 23, and articulate angularly within aplane formed by the centerlines of articulation rod 23 and shaft member13. With the tensioning knob of cylindrical post 21 loosened,articulation rod 23 is free to rotate about its longitudinal axis, isfree to translate through the cylindrical post 21 in a direction alongits longitudinal axis, is free to articulate into and out of theretracted chest cavity by increasing or decreasing the angle between itslongitudinal axis and the centerline axis of cylindrical post 21, isfree to rotate about the centerline axis cylindrical post 21, and isfree to slide within arcuate passage 81 (or either of the arcuatepassages 71 and 51). These motion degrees of freedom provide themechanical flexibility to tailor the surgical set-up to distinct patientanatomies tending to result in an ergonomic deployment of thepericardium retraction device. Cylindrical post 21 is preferably alreadyinstalled with the first articulation rod 23 on the perimeter rail 80(or perimeter rails 70 or 50) of sternum retractor 2 prior to engagingthe pericardium tissue with the pericardium retraction device 1. Thepositioning and articulation mechanism 20 serves to set the pericardiumretraction device 1, in virtually any substantially stable position andorientation within surgical workspace W and relative to a sternumretractor 2. A suitable positioning and articulation mechanism which mayadvantageously be used with the pericardium retraction device of thepresent invention is disclosed in the above-mentioned Canadian patentapplication Serial No. 2,216,893, whose specification is incorporatedherein by reference.

In this first embodiment, the tissue-engaging member 30 forms an arcuateopening for engaging the pericardium tissue. Alternatively, thetissue-engaging perimeter 311 can be configured on the front face 314 ofelastic sheath 31, the rear face 315, or any combination thereof.

Shaft member 13 is rigidly attached to the top portion of innerstructure 32 in preferably a substantially perpendicular orientationrelative to a plane containing the arcuate spine defining said innerstructure 32. Alternatively, the orientation of shaft member 13 relativeto inner structure may be varied to include other orientations. As well,a hinge joint or spherical joint may be configured at the junctionbetween shaft member 13 and inner structure 32 to result in a variableangle orientation between said components 13 and 32 depending ondirection of the application of the pericardium retraction force appliedby the surgeon.

In this first embodiment, the inner structure 32 and shaft means 13 aremanufactured from reusable, sterilizable materials approved for use insurgery, in rigid configurations. These include, but are not limited to,stainless steel, aluminum, nickel, or titanium. Alternatively, the innerstructure 32 can be designed with stiffness gradient along its definingparameters. For instance, the inner structure can be designed with avariable stiffness along its spine arcuate length in order to tend tomore closely comply to the deformed shape of the retracted pericardiumtissue. For instance, such a variable stiffness may be defined such thatthe opposed terminal ends of the inner structure 32 are less stiff thanthe portions thereof which are adjacent shaft member 13. This can beachieved through selective geometry, varying density of perforations,variable wall thickness, or by anisotropic material properties, as isachieved in variable composition polymers. Alternatively, this firstembodiment may also be a reusable, one piece construction, wherebysheath 31 and inner structure 32 are replaced by a structural outerskin. The ingestion-limiting baffle 33 is in this case mounted in arecessed position within structural outer skin with respect to thetissue-engaging perimeter 311.

In broad terms, the surgical procedure for the set-up and deployment ofthe pericardium retraction device 1 during a beating heart CABG surgery,and relating to the present invention consists of:

-   -   (a) performing a full or partial midline sternotomy incision;    -   (b) cauterizing of any bleeding vessels subsequent to the        sternotomy incision;    -   (c) if an internal thoracic artery (ITA) will be used as a        bypass conduit, retracting the two halves of the patient's        incised sternum with a surgical retractor suitable for exposing        the ITA and the surgical harvesting thereof,    -   (d) retrieving the surgical retractor used for ITA harvesting,        and inserting blades 7 and 8 of sternum retractor 2 along the        sternotomy incision;    -   (e) retracting the patient's ribcage to expose the underlying        mediastinum and pericardium tissue;    -   (f) incising the pericardium sac to expose at least a portion of        the patient's beating heart requiring the bypass graft;    -   (g) deploying the pericardium retraction device 1 by bringing        into proximity and in substantial contact with the pericardium        tissue (labelled PCT in FIG. 10) the tissue-engaging member 30;    -   (h) introducing a negative pressure suction through pericardium        retraction device 1;    -   (i) ensuring that a portion of the pericardium tissue is        properly ingested within tissue-engaging member 30 and that        adequate sealing of negative pressure occurs at the perimeter        311 of said member 30;    -   (j) while grasping handle 12, spatially orienting and        positioning the pericardium retraction device 1, with engaged        portion of pericardium tissue within its member 30, in a manner        to apply a tensile load on the pericardium tissue and thereby        simultaneously positioning and orienting the beating heart        anatomically attached to said pericardium tissue;    -   (k) maintaining the desired beating heart position and        orientation by securing the pericardium retraction device 1 to        sternum retractor 2 through positioning and articulation        mechanism 20, resulting in the desired access to the coronary        artery bed requiring the bypass graft;    -   (l) to perform bypass grafts on the inferior or posterior        coronary artery beds, preferably placing the beating heart in a        verticalized position with the longitudinal axis of the heart        assuming a substantially vertical orientation through the        rotation of the apex of the heart relative to the base of the        heart outwardly through the retracted ribcage;    -   (m) with the beating heart in the desired position and        orientation to improve surgical access to target coronary        artery, deploying a positioning and articulation mechanism 20        and associated mechanical coronary stabilizer according to the        above-mentioned copending Canadian patent application Serial No.        2,216,893, or other like positioning and heart contacting means        that allow the surgeon to perform a bypass graft on the beating        heart;    -   (n) disengaging the mechanical coronary stabilizer, or other        like means, from the surface of the beating heart after the        completion of the bypass graft;    -   (o) disengaging the pericardium retraction device 1 from its        positioning and articulation mechanism 20 and easing the beating        heart back to its natural position into the chest cavity through        the reduction of the tensile load applied through the        pericardium retraction device 1;    -   (p) turning off the negative pressure suction through the        pericardium retraction device 1 and retrieving said device 1        from retracted chest cavity;    -   (q) Closing retractor arms 3 and 4 and retrieving sternum        retractor 2;    -   (r) Closing the midline sternotomy surgical incision.

The embodiments of the pericardium retraction device that follow anddescribed in more detail below, are deployed and set up in a similarsurgical procedure as described above, provided the pericardium tissueis engaged by virtue of a negative pressure suction force.

FIGS. 5 to 7 illustrate a second embodiment according to the presentinvention. The tissue-engaging member 130 of the pericardium retractiondevice 101 is comprised of a plurality of bell-shaped suction ports 36,each demountably attached to a substantially semicircular tubular spine35 through an attachment fitting 351. This embodiment illustrates fivesuch ports, which shall be referred to as ports A, B, C, D, and E in aclockwise direction. The suction ports 36 are described in greaterdetail below. The fittings 351 are preferably arranged such that theircenterlines are substantially parallel to the centerline defining thesemicircular tubular spine 35. Alternative embodiments may haveattachment fittings 351, and consequently suction ports 36, attached tospine 35 in a variety of orientations or combination of orientations.For example, ports A, C, and E may be configured with centerlinessubstantially parallel to the centerline defining semicircular spine 35,and ports B and D may be configured with centerlines substantiallyperpendicular to the centerlines of ports A, C, and E whereby said portsextend radially outward away from the center of semicircular spine 35.

Conduit passage 10 serves to communicate the negative pressure suctionfrom a pneumatic fitting 11 at the proximal end of the pericardiumretraction device 101 to the arcuate manifold passage 355 (FIG. 6)within semicircular tubular spine 35. Semicircular spine 35 serves as amanifold to communicate the negative pressure suction to each of thesuction ports 36 through a series of inlet orifices in each of theattachment fitting 351. Orifice 140 through each of the suction ports 36comes into sealed contact with the inlet orifice in attachment fitting351 when said suction port 36 engages said spine 35 through said fitting351.

Spine 35 is attached to the distal end of shaft member 13. Gusset plates354 or the like may serve to reinforce the structural joint betweenspine 35 and shaft member 13. One attachment fitting 351 is positionedin line with the centerline of shaft member 13 in order to facilitatecleaning prior to sterilization of the integral conduit passage 10within shaft member 13. Endplugs 352 are also provided at the arc endsof spine 35 to facilitate cleaning prior to sterilization of the arcuatemanifold passage 355. The suction ports 36 are preferably manufacturedfrom an elastic polymeric material, safe for surgical use. If thepolymeric material is not suitable for repeated sterilization cycles,the suction ports 36 will be disposable elements and hence the need fora demountable assembly to rigid spine 35. Alternatively, if entirepericardium retraction device 101 is made to be disposable, theinterface between the suction ports 36 and spine 35 may be a permanentjunction.

Each of the attachment fittings 351 is embodied with an attachmentfeature 353, in this case an internal double start thread, whichinterfaces with the attachment feature 369 on suction port 36, in thiscase an external double start thread (FIG. 6). Alternative attachmentfeatures to secure suction ports 36 to the spine 35 may include: asnap-in ridge-in-groove arrangement, a retaining ring, a spring detentfeature engaging a retention groove, a flanged suction port laterallyengaging a groove feature (tongue and groove arrangement), a hingedclamping flange, a partial-turn drum cam interface, and a “peel andexpose” temporary adhesive. This latter “peel and expose” temporaryadhesive may be such that it degenerates during post-surgerysterilization cycle, thereby releasing the used suction port 36 fromattachment fitting 351 ready to receive a new pre-packaged,pre-sterilized suction port 36 with also with a said “peel and expose”adhesive.

FIG. 7 illustrates the tissue-engaging member 130 with the plurality ofdeformable suction ports 36 in their deployed shape after each hasengaged a portion of the pericardium tissue. Each of the deformablesuction ports 36 is comprised of an orifice 140, an attachment feature369, a tissue-grasping means 363, a tissue-engaging perimeter 361, andat least one deformation bias 362 disposed preferably along saidperimeter 361.

In deploying the pericardium retraction device 101 according to thissecond embodiment, while the negative pressure suction is introducedthrough the pericardium retraction device, the surgeon first contacts aportion of pericardium tissue with the engaging perimeter 361 of each ofthe suction ports 36. A substantial seal results about said perimeter361 of each of the suction ports. A portion of pericardium tissue isingested within the inside surface of each of the suction ports 36. Theseal formed at the perimeter 361 of each suction port 36 and theresultant suction force on the engaged pericardium tissue within eachsaid perimeter, causes the deformable suction port 36 to deform alongits bias 362. Folding of suction port 36 along the bias 362 (or thecollapsing of the opposing suction port 36 internal surfacessubstantially towards one another) sets the tissue-grasping means 363 oninside surface 360 in contact with the ingested pericardium tissue. Thedeformation bias 362 may be a notch (FIGS. 8A through 8D) or other likemeans which will promote a localized folding action and resultingpartial collapse of the sidewalls of the suction port 36 when suchsidewalls are subjected to radial loading due to the effect of suction.

As the surgeon manipulates the retraction device 101 to position andorient the beating heart, the tensile load on the pericardium tissueincreases due to the imposed retraction loads. Any expelling action ofthe engaged portion of pericardium tissue by virtue of the increasingretraction loads on the pericardium tissue, will engage thetissue-grasping means 363 deeper into the portion of ingestedpericardium tissue. Consequently, the retraction of the pericardiumtissue may be provided through a combination of negative pressuresuction force and a resulting mechanical grasping occurring between theinside surface 360 of suction port 36 and ingested pericardium tissue byvirtue of the grasping means 363. The tissue-grasping means 363therefore may be capable of maintaining at least a limited retractionload if the negative pressure suction force is temporarily interruptedor disabled. If it is desired to promote this effect of mechanicalgrasping in the absence of a negative pressure suction force, the tissuegrasping means are preferably in the form of protrusions which extendgenerally radially towards the center of the engaging perimeter 361 andmore preferably, also generally away from the direction in which thepericardium tissue will retract if the tensile load placed thereon isreleased. In this manner, continued engagement of the grasping means maybe promoted when a tensile load is maintained on the pericardium tissue,even in the event that the suction force acting thereon may betemporarily interrupted or disabled. However, once the tensile load isrelieved, for instance by a surgeon manipulating the pericardiumretraction device in a direction towards the patient's thoracic cavity,it is expected that the tissue grasping means will thereafter disengagefrom the pericardium tissue once the suction force is absent. Tissuegrasping means in the form of protrusions are described below withreference to FIG. 8A. Other tissue grasping means are described belowwith reference to FIGS. 8B to 8D.

The negative pressure suction force is therefore in a sense the catalystfor inducing the engagement of tissue-grasping means 363 with ingestedpericardium tissue within suction port 36. The pericardium retractiondevice 101 is positioned and secured within the surgical workspace Wthrough the positioning and articulation mechanism 20 and the sternumretractor 2 in the same manner as the first embodiment. When thesurgical intervention on the “verticalized” beating heart is completed,the pericardium retraction device 101 is displaced from itsretraction-inducing setting to a position within the surgical workspacethat relieves the tensile load on the pericardium tissue, thereby alsodisplacing the beating heart to its natural position within the chestcavity. When the negative pressure suction is turned off and the tensileload on the pericardium tissue is relieved, the deformable suction port31 resumes its original free state, the tissue-grasping means 363substantially disengages pericardium tissue, and the pericardiumretraction device may be retrieved.

The tissue-grasping means 363 is disposed along at least a portion ofthe inside surface 360 of the suction port 36, preferably along portionsof said inside surface which will be brought into opposition whensuction port 36 deforms according to its bias 362. The tissue-graspingmeans 363 is a surface treatment which promotes its adherence to theingested pericardium tissue. Several variants of the tissue-graspingmeans 363 are possible. FIG. 8A illustrates a tissue-grasping meanscomprised of pedestal-like or pin-like protrusions 364; FIG. 8Billustrates a tissue-grasping means comprised of a grid-like matrix 365;FIG. 8C illustrates a tissue-grasping means comprised of a ridgedformation such as a step-like or groove-like perimeter 366; and FIG. 8Dillustrates a tissue-grasping means comprised of a tissue adhesive-likecoating or layer 367, for instance a hydrogel coating.

The tissue-grasping means 363 may be a resultant feature from themanufacturing process which produces suction port 36. Alternatively, thetissue-grasping means may be or a feature that is introduced during asubsequent fabrication process, such as during assembly injectionmolding. For example, the tissue-grasping means may be injection moldedonto the surface 360 subsequent to the injection molding of suction port36. Alternatively, the tissue-grasping means may be a separate distinctfeature-part, permanently attached or demountably attached to insidesurface 360 of suction port 36. For example, a separate flexible metalfoil layer glued on the inside surface 360 of suction port 36,protruding metal pins embedded into inside surface 360 of suction port36.

Other variations of the second embodiment without departing from thespirit of the present invention are possible. Alternatively, instead ofa manifold arrangement, each suction port 36 may be fed by its owndesignated conduit passage 10.

Alternatively, the pneumatic fitting 11 may be incorporated with spine35 at one of the arc end locations thereby replacing one of the endfittings 352.

Alternatively, the semicircular tubular spine 35 may be of asubstantially linear shape or a substantially S-shaped inflected curveshape.

The suction port 36 may be produced from a polymeric material withvariable composition and elasticity in at least a portion of its shape,in order to cater its material properties to the desired function atthat specific location. For example, a suction port 36 may be producedwith substantially rigid attachment feature 369 and substantially rigidprotrusions defining its tissue-grasping means 363, but withsubstantially flexible and compliant tissue-engaging perimeter 361.

Alternatively, suction port 36 may have more than one bias 362 along itsperimeter 361 encouraging the desired deformed shape of suction port 36that will set the tissue-grasping means 363 in contact with the ingestedpericardium tissue.

Alternatively, the shape of the contacting perimeter 361 may besubstantially oval, substantially lens shaped, or substantiallycircular. Other shapes for the contacting perimeter 361 may also besuitable, as those skilled in this art will appreciate.

FIGS. 9A and 9B illustrates a third embodiment according to the presentinvention. The third embodiment comprises, through the provision of avalve means 380, a substantially self-sealing tissue-engaging member 38such that the flow through the pericardium retraction device 103 issubstantially zero even if the negative pressure plenum is not completedby the pericardium tissue in contact with the perimeter 384, as is therequirement in the previous embodiments.

This is advantageous in pericardium retraction devices comprised of aplurality of tissue-engaging members, when not all tissue-engagingmembers or suction ports are, or can be, in sealing contact with thepericardium tissue. Without a valve means 380, the excessive flowthrough a non sealing suction port would tend to render ineffective theremaining suction ports as well, due to the inability to generate thedesired negative pressure and consequently suction force. Alternativelyto incorporating a valve means, this problem can be alleviated byincorporating a designated conduit means 10 for each suction port. Thistends to result in a more complex, part-intensive, and consequently morecostly apparatus.

In this third embodiment, the tissue-engaging member 38 is comprised ofa hollow attachment feature 388, a source orifice 141, a diaphragmmember 387, and a spool valve means 380. The hollow attachment feature388 serves to fixture said tissue-engaging member 38 to a substantiallyrigid tubular spine (like 35) in a plurality arrangement, or directly toa shaft member 13 in a single port arrangement. The source orifice 141serves to communicate with the negative pressure source P2 throughtubular spine (like 35) and conduit member 10. The diaphragm member 387delimits a negative pressure plenum within tissue-engaging member 38.

The spool valve means 380 may assume either a “valve closed” position inwhich the negative pressure plenum P2 is delimited by diaphragm member387, as illustrated in FIG. 9A, or an “open valve” position in which thenegative pressure plenum is delimited by the engaged pericardium alongperimeter 384, and as illustrated in FIG. 9B, the substantially ambientpressure P1 drops to negative source pressure P2.

The top surface of tissue-engaging member 38 and the diaphragm member387 each are provided with a guiding and sealing bore feature 385 and386 respectively, which serve to guide the spool valve means 380throughout its travel within the tissue-engaging member 38, and alsoprovide a substantial seal with the shaft 383.

Valve means 380 is comprised of a dish-like plunger 381 which has aslot-like feature 382 to communicate plenum P2 with plenum P1 when shaft383 is plunged by the engagement of pericardium tissue around perimeter384. When the pericardium tissue is not in contact with plunger 381, thevalve means 380 assumes a stable position within the tissue-engagingmember 38 due to a pressure balance, whereby top edge slot-like feature382 is just cutting off flow through the diaphragm member 387. At the“valve closed” position, the plunger 381 is substantially proud (by adistance δ) from the tissue-engaging perimeter 384, and ready to engagethe pericardium tissue.

Plunger 381 is configured with a dish-like shape in order to easilycontact the pericardium tissue in a non-traumatic manner, but othershapes are also possible without departing from spirit of the invention.In the “valve open” position, with the plunger 381 at its topmostposition within tissue-engaging member 38, plunger 381 also acts as atissue ingestion-limiting means.

A stopper feature (not shown) to limit the translation of valve means380 within tissue-engaging member 38 may also be incorporated. Stopperfeatures may include, a stepped diameter, a key-way feature, atransverse dowel, a retaining ring, and other like limit means disposedat the terminal end of the valve means 380 which is opposite the plunger381 thereof and adjacent sealing bore 385.

A spring member (not shown) may also be incorporated to furtherencourage valve means 380 to remain in the non-flowing closed position.Initially, this spring load exerted by this said spring member must beovercome by the action of engaging pericardium tissue to plunge open thevalve means 380. This said spring load must also be overcome throughoutthe deployment of the pericardium retraction device 103 by the resultantsuction force acting on the engaged pericardium tissue.

Alternatively, instead of mechanical actuation of valve means 380through the travel of plunger 381, the valve means may be electronicallyactuated by a proximity sensor which senses the position of theunderlying pericardium tissue when said tissue is in proximity totissue-engaging member 38. The proximity sensor may be designedutilizing a light source, an electromagnetic field, or a heatmeasurement transducer, to name a few examples.

Alternatively, the concepts of this third embodiment can also be appliedto other tissue-engaging members that engage other types of coronarytissue or body tissues in general, and are not limited to engagingpericardium tissue.

The fourth embodiment according to the present invention, introduces anorgan bracing member such as a heart apex-bracing mechanism 90, whichmay be deployed in conjunction with a pericardium retraction device 100.The “verticalized” beating heart (labelled VBH in FIG. 10) and thepericardium tissue (labelled PCT in FIG. 10) anatomically attached tosaid beating heart are illustrated engaged with the apex-bracingmechanism 90 and the pericardium retraction device 100, respectively.The pericardium retraction device 100 according to the present inventionis comprised mainly of a tissue-engaging member 30, a devicemanipulating means such as shaft member 113, a conduit means such asconduit passage 110, and a suction line interface means such aspneumatic fitting 11. The tissue-engaging member 30 has already beendescribed in the first embodiment. Alternatively, other tissue-engagingmembers from other previous embodiments may also be substituted in placeof tissue-engaging member 30.

As previously described, when the beating heart is “verticalized” by wayof pericardium tissue retraction, the apex of the heart assumes asubstantially protruding orientation outward from the patient'sretracted chest cavity. The bracing means, preferably deployed in seriesafter the deployment of the pericardium retraction device, serves as astability-enhancing measure, which substantially limits the excursion ormovement of a portion of the “verticalized” beating heart, preferablythe apex. This bracing means may not be desired in all cardiac surgicalinterventions that are performed with the assistance of the pericardiumretraction device.

As illustrated in FIGS. 10 and 11, the apex-bracing mechanism 90 iscomprised of an articulation and clamping member 85, a bracing orsupporting shaft member 92, and a tissue-contacting member such as anapex-contacting member 91. The apex-bracing mechanism 90 is engaged withthe pericardium retraction device 100 through the articulation andclamping member 85 which simultaneously clamps onto the proximal portionof shaft member 13 while securing the desired position and orientationof bracing shaft member 92. A negative pressure suction source isintroduced through a pneumatic fitting 11 situated on the proximal endof extension shaft member 113. A conduit passage within extension shaftmember 113 (not shown) supplies negative pressure to both thepericardium tissue-engaging member 30 through conduit passage 110 inshaft member 13, and the apex-contacting member 91 through substantiallytubular bracing shaft member 92 and a series of passages hereunderdescribed. Consequently, since it may be desired to deploy theapex-contacting member 91 subsequent to the pericardium tissue-engagingmember 30, a valve means (like valve means 380 in the previousembodiment) is preferably contained within the said member 91.

With reference to FIG. 11, from the proximal end of conduit passage 110,the negative pressure supply enters a series of passages in the clampingmember 86, more specifically into a plenum cavity 861 into which theproximal end of conduit passage 110 is received, through an integraltransverse conduit passage 866, and through a conduit bore 869 which isdisposed generally transverse to the axial direction of conduit passage110. From the clamping member 86, the negative pressure supply entersinto hollow articulation cylinder 95 and through internal passages inbracing shaft member 92 and resilient curved member 911 to attain theapex-contacting member 91 which, in this case, serves as a negativepressure suction port. Alternately, the apex contacting means 91 can beprovided with its own designated negative pressure conduit line.

To maintain the negative pressure through component interfaces, a jointseal 84 is provided between clamping member 86 and the proximal end ofshaft member 13 at the plenum cavity 861 location. A joint seal 94 isalso provided between articulation cylinder 95 and clamping member 86 atthe conduit bore 869 location. A counterbore (not shown) may be providedwith conduit bore 869 in order to locate joint seal 94 and thecontacting perimeter of articulation cylinder 95. Seal plate 867 isprovided to cover conduit passage 866 and facilitate the machining ofsaid conduit passages within clamping member 86. Alternatively, plate867 may be eliminated if clamping member 86 is produced as a castingwith integral cored conduit passages. Alternatively, extension shaftmember 113 may be eliminated by extending shaft member 13 through theplenum cavity 861.

The articulation and clamping member 85 is comprised of clamping member83 and clamping member 86. The securing of articulation and clampingmember 85 is achieved through a threaded member 87, which is assembledin clamping member 86 through retaining pin 88 and extends through bore834 of clamping member 83 to become engaged by tensioning knob 850.Shaft member 13 is engaged laterally by surface 835 and a like surface(not shown) of clamping members 83 and 86 respectively, and axially onits topmost surface by cavity plenum 861. This secures the orientation(rotation) of clamping member 85 and bracing shaft member 92 about thecenterline of shaft member 13. Articulation cylinder 95 issimultaneously clamped between engagement surface 839 on clamp 83 and alike surface on clamp 86, thereby securing its articulation position inand out of chest cavity relative to shaft member 13 and clamping member85.

Bracing shaft member 92 is comprised of an articulation cylinder 95 andan interface joint member 932. As illustrated in FIG. 11, bracing shaftmember 92 is substantially tubular to integrate internal conduit passagefor negative pressure when apex-contacting member 91 is a negativepressure suction port. Bracing shaft member 92 may be entirely rigid, ormay be deformable only by a surgeon input, or may be a lockablemulti-jointed articulated design and construction. In all variants, thesaid member 92 is substantially rigid in that it should not yield underthe forces imposed on it by the beating heart.

Apex-contacting member 91 is comprised of a resilient curved member 911and an interface joint member 931. Resilient curved member 911 issubstantially flexible, since it will elastically yield a limited amountunder the forces imposed by the beating heart, depending on its designedstiffness. FIGS. 12A to 12D illustrate variants in the apex-contactingmember 91. FIG. 12A illustrates an apex-contacting member comprising asubstantially conical cup made from a flexible polymeric material 915;FIG. 12B illustrates an apex-contacting member comprising a plurality ofsubstantially rigid finger-like protrusions 916; FIG. 12C illustrates anapex-contacting member comprising a tissue-clamping means 917; and FIG.12D illustrates an apex-contacting member comprising a substantiallyhemi-cylindrical cradle 918 with perforations to allow anchoring to theapex tissue of beating heart with an associated suture 919.Additionally, with each of these variants, a tissue-grasping means orhydrogel coating may also be incorporated on the heart contactingsurface of the said apex-contacting member, in order to attempt toimprove the adherence to the beating heart tissue. Any of the variantsof FIGS. 12A, 12B and 12D may be utilized with the provision of asuction force or without.

The bracing shaft member 92 and apex-contacting member 91 are engaged atjunction 93, which provides the ability to rotate apex-contacting member91 about the centerline of shaft member 92. The two interface members931 and 932 comprising the said junction 93 may be rotatingly engagedthrough suction, if the apex-contacting member 91 serves as a negativepressure suction port. Alternatively, interface members 931 and 932 maybe rotatingly engaged through a magnetic attraction, through a press-fitallowing relative rotation of said interface members only through torqueapplied by surgeon's hand but not by loads exerted by the beating hearton said interface members, through a ratchet mechanism between saidinterface members, or by other like means.

In another variant of the present embodiment, junction 93 may be of atelescopic design to allow the translation, or the translation androtation of apex-contacting member 91 relative to bracing shaft member92.

Alternatively, a rotational interface replacing junction 93 may beincorporated in design of the articulation and clamping member 85.Alternatively, the articulation and clamping member 85 may be designedto allow the translation of bracing shaft member 92 along itslongitudinal axis through said clamping member 85.

With reference to FIG. 10, to deploy the apex-bracing mechanism 90 thesurgeon will preferably first position and orient the pericardiumretraction device 100 in a similar manner as described in the previousembodiments. Once the beating heart is “verticalized”, and thepositioning and articulation mechanism 20 has been secured at botharticulation members 21 and 22, the apex-bracing mechanism 90 ispositioned and oriented within the same surgical workspace W, such thatthe apex-contacting member 91 is in contact with the apex of the beatingheart and the articulation and clamping member 85 is engaged with thetopmost surface and sides of shaft member 13. This may involve therotation of the apex-bracing mechanism 90 about the centerline of shaftmember 13, the articulation of bracing shaft member 92 about thecenterline of articulation cylinder 95, and the rotation ofapex-contacting member 91 about the centerline of bracing shaft member92. The device is intended to allow for delicate presentation of theapex-bracing mechanism 90 preferably onto the apex of a “verticalized”beating heart.

The entire surgical apparatus assembly consisting of the pericardiumretraction device 100 and the apex-bracing mechanism 90, may also bepositioned and oriented within the surgical workspace W by way ofadjustment of either of the second articulation member 22 or the firstarticulation member 21, or by way of simultaneous adjustment of bothsaid articulation members 21 and 22. Consequently, the beating heart maybe re-oriented and re-positioned through a displacement of both thepericardium retraction device 100 and apex-bracing mechanism 90.

Alternatively, clamping member 85 and articulation member 22 may becombined into one mechanical assembly, preferably when theapex-contacting member 91 does not serve as a negative pressure suctionport. Clamping member 85 may be replaced with an interface sleeve thatis clamped between the second articulation member 22 and shaft member13.

Alternatively, in another embodiment, the apex-bracing mechanism 90 maybe provided with its own designated positioning and articulationmechanism 20, comprising first 21 and second 22 articulation members,and whereby said first articulation member 21 may be slidingly androtatingly engaged along rails 70, 80, or 50 of the sternum retractor 2,independently from the deployment of the pericardium retraction device100.

Alternatively, the apex-bracing mechanism 90 may also be usedexclusively in certain cardiac surgeries, without the pericardiumretraction device 100.

FIG. 13 illustrates a fifth embodiment according to the presentinvention, showing a deployed surgical retractor 2 and deployedpericardium retraction device 105. The beating heart and pericardiumtissue are not illustrated. The pericardium retraction device 105 iscomprised of a tissue-engaging member 39, a device manipulating means inthe nature of a wire-like filament 393, a conduit means such as flexibleconduit 15, and a suction line interface means such as pneumatic fitting11. The tissue-engaging member 39 is comprised of a deformablebell-shaped suction port 390 (illustrated in its deformed, deployedshape) and an attachment fitting 399. Suction port 390 is provided withthe following main features: a tissue-engaging perimeter 391, at leastone deformation bias 392 disposed preferably along said perimeter 391,and preferably a tissue-grasping means (not shown) on at least a portionof inside surface (not shown) of port 390 which comes into contact withthe ingested pericardium tissue. With the exception of wire-likefilament 393 described below, the suction port 390 is of similarconstruction to the suction port 36 of the second embodiment. Thefunction of said port 390 and the cooperation of its constituentfeatures having been previously described by similarity through thedescription of suction port 36 in the second embodiment.

In this embodiment, pericardium tissue is retracted by at least onepericardium retraction device 105. The beating heart is preferably“verticalized” by a plurality of tissue-engaging members 39, eachsupplied by its own designated conduit 15, and each being securedindependently to a sternum retractor 2 through the anchoring ofwire-like filament 393. The conduit 15 is a flexible tubular membertending to facilitate its placement within the surgical workspace W withan aim not to encumber access into the retracted chest cavity.Alternatively, conduit 15 may also be a malleable tubular member whichthe surgeon may deform into a desired less obstructive shape.

The proximal end of conduit 15 is configured with a pneumatic fitting 11which may be connected to a negative pressure supply line in theoperating room or to a negative pressure manifold along with severalother pneumatic fittings when a plurality of pericardium retractiondevices 105 are deployed. The suction port 39 is attached to conduit 15through an attachment fitting 399, in either a demountable or permanentassembly as also described by similarity in the second embodiment.Negative pressure is supplied to the suction port 39 through an orificefeature in attachment fitting 399 which communicates with conduitpassage 10 within conduit 15.

A wire-like filament 393 is attached to the attachment fitting 399 andserves as a device manipulating means allowing the surgeon to apply thedesired tensile retraction load to the pericardium tissue by a pullingaction on said wire-like filament. The desired pericardium retractionload to position and orient the beating heart is maintained during thesurgical intervention by securing the free proximal end of filament 393to sternum retractor 2, through a variety of anchoring mechanisms andmethods. For instance, the free end of filament 393 may be inserted andpartially threaded through an opening in a filament clamp 395. Filamentclamp 395 is comprised of two cooperating jaws which exert a clampingload on the portion of filament 393 clamped therebetween. An adjustmentmeans 394 is also provided within filament clamp 395, which whenactivated, serves to temporarily relieve the clamping action of two saidjaws thereby allowing the repositioning of filament clamp 395 along thelength of filament 393. The adjustment means 394 may be activated by avariety of methods, such as for instance through the application of amanual compression force on the adjustment means. Filament 393 isinserted in a slit-like channel 72 or 82. With the desired pullingaction applied to the filament 393 to achieve pericardium retraction,the filament clamp 395 is repositioned along the length of filament 393and brought into contact with spreader arm 3 or 4 of sternum retractor2. By virtue of the imposed retraction load on pericardium tissue, clamp395 is wedged against spreader arm 3 or 4 when filament wire 393 isinserted in slit-like channel 72 or 82. The clamping action of the jawson filament 393 secures the resulting filament length between attachmentfitting 399 and filament clamp 395 thereby maintaining the pericardiumand resulting filament length in tension during the surgical procedure.

A variety of other methods may be used to secure the desired length offilament 393 relative to a portion of sternum retractor 2 in order tomaintain the desired pericardium retraction load. For instance, theanchoring mechanisms described in copending Canadian patent applicationSerial No. 2,242,295 filed on Aug. 10, 1998 in the names of Paolitto etal. and entitled “Surgical Instruments for Tissue Retraction”, for whicha corresponding PCT application has been filed on Aug. 10, 1999 in thenames of Paolitto et al. and entitled “Surgical Suture and AssociatedAnchoring Mechanism”, the contents of which are incorporated herein byreference, may be used as they relate to the securing of a tensileloaded wire-like filament to a surgical retractor. These existingapplications have been assigned to CORONEO Inc., the assignee of thepresent application.

Alternatively, a variant to the present fifth embodiment may consist ofhaving one conduit 15 supplying negative pressure suction to more thanone suction port 39 disposed at its distal end through a manifold typeattachment fitting, as previously described.

FIG. 14 illustrates a sixth embodiment according to the presentinvention. In this embodiment, the deformable suction port 39 isreplaced by an alternate mechanical tissue-engaging member such as atissue clamp 396. The pericardium retraction device 106 is comprised ofa tissue clamp 396, a device manipulating means in the nature of awire-like filament 393, and an anchoring mechanism in the nature of afilament clamp 395.

The tissue clamp 396 is comprised of at least two clamping members whichthe surgeon or assistant manipulates in a manner to clamp therebetween aportion of the pericardium tissue. Examples include a snap-tight clampor spring-loaded clamp. The tissue clamp 396 is engaged with pericardiumtissue without having to pierce through said pericardium tissue,therefore tending to reduce the likelihood of inducing injury tounderlying body tissue behind unraveled pericardium tissue.

The imposed clamping loads on the portion of pericardium tissue engagedwithin tissue clamp 396 is sufficient to overcome the retraction forcesexperienced during “verticalization” of the beating heart. The filamentclamp 395 and adjustment means 394 are the same as those described inthe fifth embodiment and may also be replaced by a variety of otheranchoring mechanisms referred to above.

FIG. 15 illustrates a seventh embodiment according to the presentinvention. This embodiment incorporates a negative pressure conduitmeans into the positioning and articulation mechanism, with an aim toimproving the ergonomics of the surgical workspace W. The pericardiumretraction device 102 is comprised of a tissue-engaging member 30 (whichis the same as in the first embodiment), a device manipulating meanssuch as shaft member 131, and a conduit means such a conduit passage 10.The positioning and articulation mechanism 120 is similar to thepositioning and articulation mechanism 20 of the previous embodimentsexcept for the modifications introduced to incorporate a conduit meansthereof. A pneumatic fitting 11 is provided on the proximal end of firstpositioning rod 25. An internal conduit passage 250 within rod 25 spansthe entire length of the said rod, from the fitting 11 inlet to thespherical rod end 251. A flexible tubular coupling 253 plugs into thespherical rod end 251 of rod 25 at junction interface 252. The flexibletubular coupling 253 extends through a portion of shaft member 131 tocommunicate with conduit passage 10 within said shaft member 131. Thepericardium retraction device 102 is engaged within the clamping members262 of the second articulation member 26 and secured between saidclamping members 262 by tensioning knob 261. The flexible tubularcoupling 253 allows for a substantially similar deployment andsubstantially similar motion degrees of freedom of mechanism 120relative to the positioning and articulation mechanism 20 of theprevious embodiments.

In the embodiments of the present invention requiring a negativepressure supply, the source for this said negative pressure may beeither a suction line generally available in operating rooms, oralternatively an auxiliary vacuum pump to provide an independentnegative pressure supply or a pressure boost to the suction available inthe operating room.

In the embodiments of the present invention described herein, it isintended to produce the bulk of the surgical apparatus from reusablecomponents, whose assembly may be at least partially dismantled, ifnecessary, for ease of sterilization. All components are manufactured ineither surgical grade stainless steel, titanium, aluminum or any otherreusable sterilizable material suitable for surgical use. Componentsproduced from polymeric materials are either reusable through specificsterilization procedures tailored to these component materials, or mustbe replaced after every use or after a predetermined number of uses ifthe polymeric material properties are not suitable for sterilization ordegrade after repeated sterilization cycles. However, any number of thesaid reusable components may also be produced from disposable surgicalgrade plastics, if the case for disposable components is warranted andif the engineering and functional intent is maintained when the saidcomponent is produced from plastic.

Some of the features and principles of the embodiments of the presentinvention may advantageously be applied, if desired, to other surgicalapparatus used for engaging body tissue through a negative pressuresuction port. The above description of the embodiments of the presentinvention should not be interpreted in any limiting manner sincevariations and refinements are possible without departing from thespirit of the invention.

1. A surgical method for performing a surgical intervention on a target anatomic structure of a patient body, said patient body also including non-target anatomic structures and defining a thoracic cavity, said thoracic cavity including a patient's heart, said heart being substantially contained within a pericardium tissue and anatomically attached to at least a portion thereof, said thoracic cavity also defining a thoracic peripheral wall, said thoracic peripheral wall including a rib cage, said target anatomic structure being located within said thoracic cavity, said surgical intervention involving the use of a pericardium retraction device and surgical platform, said surgical platform being configured and sized for receiving at least a portion of said pericardium retraction device, said method comprising the steps of: incising said pericardium tissue to expose at least a portion of said heart; introducing said pericardium retraction device at least partially into said thoracic cavity of said patient body; bringing said pericardium retraction device in negative pressure suction contact with at least a portion of said pericardium tissue; positioning said pericardium retraction device in a retracting configuration wherein said pericardium retraction device provides a tensile load on said contacted pericardium tissue thereby positioning said heart being anatomically attached to said pericardium tissue within said thoracic cavity.
 2. A surgical method as recited in claim 2 further comprising the step of at least temporarily coupling said pericardium retraction device to said surgical platform in said retracting configuration. 